Portion of a light bulb



FIG. 1 is a perspective view of a portion of a light bulb;

FIG. 2 is a front side view thereof;

FIG. 3 is a rear side view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken line showing of the light bulb housing and glass is for the purpose of illustrating the portion of a light bulb and forms no part of the claimed design. 

CLAIM I claim the ornamental design for a portion of a light bulb, as shown and described. 